In one embodiment of the present invention, an apparatus for detecting a hot
rail
car surface comprises: an infrared sensor for acquiring an infrared signal from
a rail car surface of a rail car and transducing the infrared signal into an electrical
signal; a rank filter for filtering the electrical signal to produce a filtered
array; a first peak detector for detecting a maximum filtered value of the filtered
array; and a first comparator for comparing the maximum filtered value to a detection
threshold to produce a filtered alarm signal.
